The primary goal of this program is to further our understanding of the molecular basis of thrombotic disease. In this regard, the group of eight clinical and basic scientists have joined together to undertake fundamental studies on blood coagulation and related phenomena. These studies include structural studies on fibrinogen and fibrin, platelet physiology and biochemistry, the biocompatibility of materials, fibrinolysis and thrombin inhibitors. During the forthcoming year it is anticipated that the remaining principal polymerization sites on the fibrinogen molecule will be identified, and with that a virtually complete understanding of the molecular basis of fibrin formation achieved. In other areas, a further characterization of human factor VII has been proposed, as well as further investigation of a newly discovered prothrombin polymorphism. Studies on clotting inhibitors and fibrinolysis activators will be continued.